Voltage Stability Study of the PJM System Following Extreme Disturbances

This paper presents results from an analysis of voltage stability following severe contingencies in the PJM system. The analyses involved the use of steady-state (OPF) and short- and long-term simulation tools. The results highlight the importance of adequate load modeling in assessing the performance of and solutions to voltage instability. Undervoltage load shedding (UVLS) is shown to be beneficial in arresting instability. Optimal power flow (OPF) analyses (supplemented with dynamic simulation results) provide valuable insight into the best locations and required minimum levels of UVLS. However, UVLS may not be able to address the serious scenarios where fast voltage dynamics develop immediately after an outage